flump vs sit down

flump

verb
  • To move or fall heavily, or with a dull sound. 

  • To drop something heavily or with a dull sound. 

noun
  • A type of large marshmallow. 

  • A fat out-of-shape person. 

  • The dull sound so produced. 

sit down

verb
  • To assume a low or sunken position. 

  • To meet formally at a conference table. 

  • To cause to be seated or in a sitting posture; to furnish a seat to. 

  • To assume a sitting position from a standing position. 

How often have the words flump and sit down occurred in a corpus of books? (source: Google Ngram Viewer )